A couple of months ago I was doing some work on guard pages in libc_r and
discovered that using 'cat' to view the VM map for a process is
unreliable. This fact is documented in the proc code, and there is even an
explanation of how to reliably read the map files. However, I could find
no program that actually does this, so I wrote one.
The program is attached (yes, it needs a man page if it is to be imported),
but my question is whether it belongs in the source tree, and if so, where?
Thanks,
Jason
/*
* Copyright (C) 2000 Jason Evans <[EMAIL PROTECTED]>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#define MAXPATH 18
#define MINBUF 4096
int
main(int argc, char ** argv)
{
char * buf;
char path[MAXPATH] = "/proc/"; /* Big enough for "/proc/curproc/map". */
int mfd, bytes, size = MINBUF;
if (argc != 2) {
fprintf(stderr, "usage: procmap {<pid> | curproc}\n");
exit(1);
} else if (strlen(argv[1]) > 7) {
fprintf(stderr, "procmap: <pid> too long.\n");
fprintf(stderr, "usage: procmap {<pid> | curproc}\n");
exit(1);
}
/* Open the map file. */
snprintf(path, MAXPATH, "/proc/%s/map", argv[1]);
mfd = open(path, O_RDONLY);
if (mfd < 0) {
fprintf(stderr, "Unable to open() %s: %s\n",
path, strerror(errno));
exit(1);
}
/*
* Start out with a MINBUF byte buffer, and double the buffer size until
* it's big enough to read the whole map at once.
*/
buf = (char *) malloc(size);
if (buf == NULL) {
fprintf(stderr, "malloc() error\n");
exit(1);
}
bzero(buf, size);
while (1) {
if (lseek(mfd, 0, SEEK_SET) < 0) {
fprintf(stderr, "lseek() error: %s\n",
strerror(errno));
exit(1);
}
/* Leave space for a NULL terminator at the end of buf. */
if (bytes = read(mfd, buf, size - 1) < 0) {
if (errno == EFBIG) {
/* Buffer to small; try again. */
size <<= 1;
buf = (char *) realloc(buf, size);
if (buf == NULL) {
fprintf(stderr, "realloc() error\n");
exit(1);
}
bzero(buf, size);
} else {
fprintf(stderr, "read() error: %s\n",
strerror(errno));
exit(1);
}
} else {
/* Success. The results are in buf. */
break;
}
}
/*
* Write out a header.
*
* format: start, end, resident, private resident, cow, access, type.
*/
printf("start end resident priv_res cow access type\n");
printf("%s", buf);
return 0;
}
